1. Field of the Invention
The present invention relates to a collision reaction force measurement apparatus, and, in particular, a collision reaction force measurement apparatus for measuring a collision reaction force applied to a portable electronic device or such when it drops.
2. Description of the Related Art
For example, for a so-called portable electronic device such as a cellular phone, a notebook-type personal computer or such, in addition to miniaturization and reduction of a product weight, enhancement of various functions has been achieved, and simultaneously, it is demanded that such a product should have a sufficient mechanical strength against a dropping impact —which must be presumed, in consideration of how it is used. As a method of evaluating a mechanical strength of a product against a dropping impact, a collision reaction force measurement apparatus may be used. Unlike another measurement method in which the measurement is carried out with an acceleration sensor or a strain gage directly attached to the product itself, the method of using the collision reaction force measurement apparatus is advantageous in that, since a sensor cable or such which may affect an actual dropping position of the measurement target object is not required, it is possible to carry out highly reproducible evaluations.
As a specific example of the collision reaction force measurement apparatus, a configuration shown in FIG. 1 may be considered. In this configuration, a collision table 1 is provided on a load cell 2, a measurement target object 3 is made to drop on the collision table 1, and then, a collision reaction force thus occurring is measured by the load cell 2. However, in the collision reaction force measurement apparatus having the configuration shown in FIG. 1, if the measurement target object collides at a position deviated from a center of the load cell 2, a relevant impact is applied to the load cell 2 in a form of a torque, and as a result, it may be difficult to accurately measure the collision reaction force.
Japanese Patent No. 3404291 discloses a method for solving this problem for example in which three load cells 2-a, 2-b and 2-c arranged at vertexes of a triangle are provided, and then, as a result of combining measurement outputs of the respective ones of the load cells 2-a, 2-b and 2-c, a collision reaction force of a measurement target object X is obtained finally.